🪵 Free US Fence Calculator — 5 Fence Styles + Shadowbox Overlap + Posts + Rails + Gate Deduction

Fence Picket Calculator: Pickets, Posts, Rails, and Cost for Privacy, Shadowbox Board-on-Board

The only US fence calculator with 5 fence style modes including the mathematically complex shadowbox/board-on-board overlap calculation (requires 35% more boards than a simple privacy fence), automatic gate opening deduction from picket counts, post count breakdown by type (line, end, corner, gate), rail board count, and a cost-per-linear-foot metric.

🪵 Fence Picket Calculator

Step 1 — Fence Style
Zero gap between boards — fully butted for maximum privacy. Each board is set tight against the next. Standard for cedar dog-ear privacy fences.
in gap
in overlap
🔄 Shadowbox overlaps each alternating board by 1–2 in. More overlap = more boards needed but better wind performance. 1.5 in is the US standard.
Step 2 — Fence Dimensions
ft
ft
ft
Step 3 — Gates and Post Types
gates
ft
sets
posts
posts
📐 Gate posts = 2 posts per gate (one each side). For a standard single-gate fence line with 2 ends + 2 corners + 1 gate, enter: end posts=2, corner posts=2, gate posts=1 (set). Total = calculated automatically.
Step 4 — Optional Cost Estimate
$
$

📊 Your Fence Materials

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Choose fence style, enter total length, gate count, post types — then click Calculate Fence for picket count (with BOB overlap if shadowbox), post breakdown, rails, and cost per linear foot.

Fence Picket Calculator: Why Shadowbox Fences Need 35% More Boards Than a Simple Privacy

The most common lumber-ordering mistake for fence projects is using a simple privacy fence formula for a shadowbox (board-on-board) fence. A privacy fence is straightforward: length in inches ÷ board width = boards needed. A shadowbox is fundamentally different — boards alternate between the front face and the back face of the rails with a 1–2 inch overlap between adjacent boards on each face. To calculate shadowbox correctly, you first calculate how many boards you’d need for one solid face, then multiply by approximately 1.35 (for 1.5-inch overlap with 5.5-inch boards) because the alternating pattern requires more boards per linear foot of fence than a simple butt-joint privacy fence.

The actual shadowbox multiplier depends on your board width and overlap amount. With 1×6 boards (5.5 in actual) and 1.5 in overlap, the effective “coverage” per board is 5.5 − 1.5 = 4.0 inches. For a standard privacy fence with 1×6 boards (no gap), coverage is 5.5 inches per board. Dividing: 5.5 ÷ 4.0 = 1.375 — so shadowbox needs about 37.5% more boards than a solid privacy fence for the same linear footage. Most fencing contractors round up to 35–40% more. This calculator applies the exact multiplier based on your overlap setting so you order the right quantity the first time.

Quick picket count formulas by fence style: Privacy (solid): boards = ceil(net_length_in / board_width_in). Shadowbox: boards = ceil(net_length_in / (board_width − overlap)) × both sides factor. Decorative picket: boards = ceil(net_length_in / (board_width + gap)). Stockade panels: panels = ceil(length / 8). Net length = total fence length minus gate openings. Always add 10% for waste and cuts. Post count: line posts = bays − 1; add end posts, corner posts, gate posts separately.

US Fence Style Reference: Picket Math, Board Count, and Post Spacing

Fence StyleGap/OverlapRails/BayBoards vs. PrivacyPost OCBest Use
Privacy (Solid)0 in gap3Baseline (1.0×)8 ftFull privacy, maximum screening. Butted boards. Most common residential fence style in the US.
Shadowbox / Board-on-Board1–2 in overlap3~1.35–1.4×8 ftFull privacy from any angle + wind flexibility (boards can flex independently). More expensive than solid.
Decorative Picket2–4 in gap20.5–0.7×6–8 ftClassic American picket look. Open and airy. Not a privacy fence — typically 3–4 ft tall. 1×4 Gothic boards.
Stockade Panels0 (pre-built)IncludedN/A — count panels8 ftPre-assembled 6×8 ft sections. Easiest and fastest installation. Good for DIY projects.
Split Rail (2-Rail)N/A — no pickets2N/A — only rails8–10 ftOpen ranch or rustic style. No pickets at all — just horizontal rails. Good for property marking, gardens.

Three Real US Fence Projects: Calculations and Material Lists

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Example 1: Dallas, TX: 150 ft Cedar Dog-Ear Privacy Fence, 6 ft, 8 ft Post Spacing

Dallas, Texas — backyard privacy fence, cedar 1×6 dog-ear boards, standard 8 ft posts, one 4-ft pedestrian gate

A Dallas homeowner is replacing a rotted 6-foot privacy fence around a 150-foot backyard perimeter. Cedar 1×6 dog-ear boards, 8-foot post spacing, one 4-foot pedestrian gate, 2 end posts, 2 corner posts. He wants the full material list before calling a lumber yard.

StepCalculation
Fence length150 ft total
Gate deduction150 − 4 = 146 ft net
Board count146 × 12 in ÷ 5.5 in = 318.5 → 319 boards
+10% waste319 × 1.10 = 350.9 → 351 boards to order
Fence baysceil(146 ÷ 8) = 19 bays
Line posts19 − 1 = 18 interior posts
Total posts18 line + 2 end + 2 corner + 2 gate = 24 posts
Rails (3 per bay)19 × 3 = 57 rails
Cost (est.)351 × $4.50 + 24 × $8.00 = $1,579.50 + $192 = ~$1,772 materials
Cost/linear ft$1,772 ÷ 150 = $11.81/linear ft
✅ Dallas tip: Texas A&M AgriLife Extension recommends cedar as the top choice for Texas privacy fences — rot-resistant without chemical treatment, stands up to Texas heat, and is widely available at Dallas-area lumber yards. For cedar dog-ear 1×6 boards at 8-ft post spacing, the standard 3-rail design (bottom, center, top) is required for 6-ft fence height. Use 4×4 cedar posts set 2 ft into the ground (with 1/3 of post length in ground + 6 in of concrete). Texas A&M AgriLife at agrilifeextension.tamu.edu has a free Fencing Selection Guide for Texas homeowners.
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Example 2: Cincinnati, OH: 80 ft Shadowbox Board-on-Board, 1×6 Cedar, 1.5 in Overlap

Cincinnati, Ohio — side yard shadowbox fence, 80 ft, 1×6 cedar, 1.5 in overlap, 2 corners, no gates

A Cincinnati homeowner wants a shadowbox fence for the side yard — full privacy from neighbors but wind flexibility because the yard is exposed. 1×6 cedar, 1.5-inch overlap, 8-foot post spacing, 2 corner posts, 2 end posts, no gates.

StepCalculation
Net fence length80 ft (no gates)
Effective coverage per board5.5 in width − 1.5 in overlap = 4.0 in per board
Standard privacy boards80 × 12 ÷ 5.5 = 174.5 boards
BOB multiplier5.5 ÷ 4.0 = 1.375×
Shadowbox boards175 × 1.375 = 240.6 → 241 boards
+10% waste241 × 1.10 = 265.1 → 266 boards to order
Bays / posts10 bays → 9 line + 2 end + 2 corner = 13 posts
Rails (3 per bay)10 × 3 = 30 rails
Extra boards vs. privacy266 BOB − 192 solid = 74 extra boards (38% more)
✅ Cincinnati tip: Ohio State University Extension identifies the shadowbox (board-on-board) style as the fastest-growing fence style in Ohio because of its combination of full visual privacy with wind load flexibility — an important advantage in the Cincinnati area which sees significant windstorms and thunderstorms. OSU Extension at extension.osu.edu has a free Home Fencing Guide with Ohio building code post depth requirements (minimum 18-inch depth below frost line for Central Ohio = 36-42 inches total depth for a 4×4 post) and local lumber species recommendations.
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Example 3: Portland, ME: Decorative Gothic Picket Fence, 40 ft, 1×4 boards, 2.75 in Gap

Portland, Maine — front yard decorative picket fence, 40 ft, 1×4 Gothic cedar, 2.75 in gap, 4 ft tall

A Portland homeowner wants a traditional New England Gothic-top decorative picket fence for the front yard. 1×4 cedar Gothic boards, 2.75-inch gap between boards, 4-foot fence height, 6-foot post spacing (shorter spans look better with decorative fences), one 4-foot gate.

StepCalculation
Net fence length40 − 4 = 36 ft net
Effective width per board3.5 in actual width + 2.75 in gap = 6.25 in per space
Pickets needed36 × 12 ÷ 6.25 = 69.1 → 70 pickets
+10% waste70 × 1.10 = 77 → 77 pickets to order
Bays (6 ft spacing)ceil(36 ÷ 6) = 6 bays
Posts5 line + 2 end + 2 gate = 9 posts
Rails (2 per bay, 4 ft fence)6 × 2 = 12 rails
Cost (est. $2.25/picket + $6/post)77 × $2.25 + 9 × $6 = $173 + $54 = ~$227 materials
✅ Portland tip: University of Maine Extension recommends white cedar (arbor-vitae) as the top choice for decorative fence boards in Maine — it grows locally, resists rot in Maine’s wet climate, and is lighter than western red cedar. For Gothic-top pickets, Maine lumber yards typically stock 1×4×4 white cedar pointed pickets pre-cut. UMaine Extension at extension.umaine.edu has a free Selecting Lumber and Fencing Materials guide for the Maine climate.

Three Expert Tips for Fence Installation

1

Set Posts 1/3 of Their Total Length in the Ground: Plus 6 Inches of Concrete

The most common fence failure point is posts that pull out of the ground or lean after a few winters. The rule: the portion of the post in the ground should be at least 1/3 of the total post length. For an 8-foot post used in a 6-foot fence (2 feet above ground plus 2 feet in ground = barely adequate), upgrade to a 9-foot or 10-foot post so you have 3–3.5 feet in the ground. In frost-prone areas (anywhere that sees sustained freezing temperatures), posts must be set below the local frost line to prevent heaving — typically 36–42 inches in northern US states. Dig the hole with a post-hole digger to the correct depth, pour 6 inches of fast-setting concrete in the bottom, set the post, level it, then fill the remaining hole with concrete tapering slightly away from the post at the top to shed water. Let concrete cure 48–72 hours before framing the fence.

2

Order an Extra 10% of Materials Before Starting: Not After the Project Is Halfway Done

Every fence project has cuts, splits, and boards with defects. The 10% waste factor in this calculator is the industry standard and is especially important for cedar fence boards, which can have knots, cupping, and grain variations that make some boards unusable. The critical mistake is ordering exact quantities and then running short mid-project — making a second lumber run costs time and often means getting boards from a different batch that don’t match exactly in width (lumber dimensions can vary slightly between production runs). Order your full quantity including the 10% buffer before starting. Unused boards can often be returned, but check the return policy before ordering — most lumber yards accept returns within 30 days with receipt.

3

Check Local Building Codes and HOA Rules Before Ordering Any Materials

In most US municipalities, residential fences require a building permit if they exceed 6 feet in height or front yard fences over 4 feet. Many jurisdictions have setback requirements (fence must be 2–6 feet inside the property line, not on the line), and some prohibit solid privacy fences in front yards. Homeowners Associations (HOAs) frequently specify allowed fence styles (no stockade, must be picket), materials (no chain link in front yard), colors, and maximum heights. Violating these rules can result in mandatory fence removal at the homeowner’s expense. Before purchasing any materials: (1) check with your local building department about permit requirements, (2) review HOA rules if applicable, (3) confirm your property line location — having a neighbor dispute your fence location after installation is extremely costly and legally complex. Call 811 before digging any fence post holes to locate underground utilities.

Frequently Asked Questions About Fence Picket Calculations

How many fence pickets do I need per linear foot?+
Depends on board width and style. Per linear foot: 1×6 privacy (5.5 in, no gap): 12 ÷ 5.5 = 2.18 boards/ft. 1×6 shadowbox (1.5 in overlap): 12 ÷ 4.0 = 3.0 boards/ft per face, ×1.375 multiplier. 1×4 decorative (3.5 in, 2.75 in gap): 12 ÷ 6.25 = 1.92 boards/ft. For a 150-ft fence: 1×6 privacy = ~328 boards. 1×6 shadowbox = ~451 boards. 1×4 picket = ~289 boards. Always add 10% for waste and cuts.
What is a shadowbox fence?+
A shadowbox fence (also called board-on-board) alternates fence pickets on opposite sides of the horizontal rails — one board on the front face, the next board on the back face, with each board overlapping the adjacent one by 1–2 inches. This creates full privacy when viewed straight on while allowing air movement between the overlapping boards (good for windy areas). It requires approximately 35–40% more boards than a solid privacy fence for the same linear footage. The shadowbox style is popular in the Southeast and Midwest for residential backyard fencing.
What is the standard post spacing for a wooden fence?+
8 feet on-center is the US standard for most residential wooden fences. This minimizes the number of posts while keeping rails structurally adequate. For decorative picket fences (shorter, lighter), 6 ft spacing is common for a more refined look and stiffer rails. For split rail fences on large lots, 10 ft spacing is used. Post spacing affects rail cost significantly: 8-foot spacing requires one rail per bay; 10-foot spacing requires longer (or doubled) rails to avoid sagging. Never exceed 10 feet between posts for wooden fences in windy or high-traffic areas.
How many rails does a 6-foot fence need?+
A 6-foot-tall wooden fence needs 3 horizontal rails for adequate structural support: one near the top (6–12 in from top), one near the bottom (6–12 in from ground), and one in the middle (at approximately 3 ft height). 4-foot fences typically use 2 rails (top and bottom). Rail board length should match post spacing — 8-foot rails for 8-foot post spacing. Total rails = number of bays × rails per bay. This calculator automatically calculates the correct rail count for each fence style.
What is the actual width of a 1×6 fence board?+
US lumber is sold by “nominal” dimensions which are always larger than the actual dimensions: 1×4 nominal = 3.5 inches actual width. 1×6 nominal = 5.5 inches actual. 1×8 nominal = 7.25 inches actual. The nominal measurement (1×6) refers to the rough-sawn dimension before drying and planing. Always use the actual width for picket count calculations — using 6 inches instead of 5.5 inches for a 1×6 board creates a significant calculation error over a long fence run. This calculator automatically uses actual widths for all standard board sizes.
Do I need a permit to build a fence?+
Usually yes for fences over 6 feet tall or in front yards over 4 feet. Permit requirements vary significantly by US municipality: most US cities require a permit for any fence over 6 feet. Front yard fences: many jurisdictions limit to 4 feet and require permits. Proximity to sidewalks, easements, and utility right-of-ways: many cities require fences to set back 2–6 feet. HOA rules: often stricter than city codes. Fences on or near the property line: may require survey verification. Check with your local building department before starting — a fence built without required permits may need to be removed. The US fence building code database is not centralized, so always verify with your specific municipality.
How deep should fence posts be set?+
The standard rule: posts in the ground = 1/3 of total post length (minimum). For a 6-ft fence height needing 2 ft in ground: use a 9 or 10 ft post. For frost areas (soil that freezes): posts must be set below the frost line. Frost line depth by region: Upper Midwest (MN, WI, ND): 42–60 inches deep. Northeast (NY, MA, ME): 36–48 inches. Mid-Atlantic (PA, OH, IN): 30–36 inches. Southeast (NC, VA, TN): 12–18 inches. Southwest: minimal. Set concrete 6 inches below the post bottom for secure footing. Posts for gates and corners need to be set deeper and with larger diameter holes (12 in diameter vs. 8–10 in for line posts) because they bear more stress.
How many fence posts do I need per 100 feet?+
At 8-foot post spacing: 100 ft ÷ 8 = 12.5, so approximately 13 bays = 12 line posts + 2 end posts = 14 total. At 6-foot spacing: 100 ft ÷ 6 = 16.7 bays = 16 line + 2 end = 18 posts. Add corner posts (1 per corner) and gate posts (2 per gate) to these totals. A typical backyard with a roughly rectangular perimeter needs: interior line posts (most), 4 corner posts, 2 end posts (where fence meets house), and 2 gate posts per gate. This calculator separates all post types for an accurate total count.
What is the average cost of a wooden fence per linear foot?+
US average costs for installed wooden fence: Decorative picket (1×4, 4 ft): $8–$15/linear ft installed. Privacy fence (1×6, 6 ft): $14–$25/linear ft installed. Shadowbox/BOB (1×6, 6 ft): $17–$30/linear ft installed. Stockade panels (6 ft): $12–$22/linear ft installed. Split rail (2-rail, 4 ft): $8–$15/linear ft installed. Labor typically runs $8–$15/linear ft on top of materials for professional installation. This calculator shows the materials-only cost per linear foot — add 50–100% for fully installed cost estimates in most US markets (labor costs vary significantly by region).
How do I calculate fence posts for corners and gates?+
Corner posts: each 90-degree corner requires 1 corner post (where the fence changes direction). A rectangular backyard has 4 corners = 4 corner posts. End posts: where the fence terminates (typically where it meets the house or property boundary). A simple backyard fence has 2 end posts. Gate posts: each gate opening requires 2 gate posts (one on each side of the opening). Gate posts must be set deeper and larger than line posts because gates apply lateral stress from swinging. For a double gate: 2 posts for the center of the double opening + the gate posts on outer sides. This calculator takes your corner, end, and gate post inputs separately for accurate total count.

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Legal Disclaimer and Editorial Transparency

Fence material quantities in this calculator are estimates for planning purposes. Actual quantities vary by fence design, lumber defect rates, gate configurations, and local material specifications. Always verify local building permit requirements and property line locations before installation. Fence heights and setbacks are regulated at the municipal level in the US — requirements vary significantly by city and state.

Regional guidance references Texas A&M AgriLife Extension (agrilifeextension.tamu.edu), Ohio State University Extension (extension.osu.edu), and University of Maine Extension (extension.umaine.edu). Call 811 before digging fence post holes: call811.com. USCalculators.com is not affiliated with any lumber supplier, fence contractor, or building supply company.